Entropy Generation and Natural Convection of CuO-Water Nanofluid in C-Shaped Cavity under Magnetic Field

Abstract

This paper investigates the entropy generation and natural convection inside a C-shaped cavity filled with CuO-water nanofluid and subjected to a uniform magnetic field. The Brownian motion effect is considered in predicting the nanofluid properties. The governing equations are solved using the finite volume method with the SIMPLE (Semi-Implicit Method for Pressure Linked Equations) algorithm. The studied parameters are the Rayleigh number (1000 ď Ra ď 15,000), Hartman number (0 ď Ha ď 45), nanofluid volume fraction (0 ď φ ď 0.06), and the cavity aspect ratio (0.1 ď AR ď 0.7). The results have shown that the nanoparticles volume fraction enhances the natural convection but undesirably increases the entropy generation rate. It is also found that the applied magnetic field can suppress both the natural convection and the entropy generation rate, where for Ra = 1000 and φ = 0.04, the percentage reductions in total entropy generation decreases from 96.27% to 48.17% for Ha = 45 compared to zero magnetic field when the aspect ratio is increased from 0.1 to 0.7. The results of performance criterion have shown that the nanoparticles addition can be useful if a compromised magnetic field value represented by a Hartman number of 30 is applied.

Effect of a Magnetic Quadrupole Field on Entropy Generation in Thermomagnetic Convection of Paramagnetic Fluid with and without a Gravitational Field

“…Such irreversibilities may be caused by heat transfer across the finite temperature gradient, viscous dissipation and magnetic field effects, etc. The magnetic field influence on entropy generation in nanofluid-filled cavities has been exposed in the recent literature [26][27][28]. The results showed that the magnetic field and the presence of nanoparticle had a substantial influence on flow pattern, heat transfer, and entropy generation.…”

Mixed Convection and Entropy Generation of an Ag-Water Nanofluid in an Inclined L-Shaped Channel

“…The criterion of thermal performance against the generation of entropy that was proposed in past papers [36,37] is defined here in an inverse form as:…”

“…Following Bejan's conclusions from these books, several studies have been published in this topic under different engineering circumstances. An analysis of entropy generation in enclosures with and without a nanofluid can be found in several past studies [29][30][31][32][33][34][35][36][37]. These studies recorded an increase in entropy generation with an increasing ratio of inertial to viscous forces, while there was conflict between heat transfer irreversibility and the volume fraction of nanoparticles.…”

MHD mixed convection and entropy generation of water–alumina nanofluid flow in a double lid driven cavity with discrete heating

“…Prototypical structure of heat transfer procedure in various industries is acquired with an accurate measurement of entropy generation since it clarifies waste of energy in a process. Hence, entropy generation is examined into mixed convection of pure and nanofluid [28,29,30,31,32,33,34,35,36,37,38].…”